A regular dot pattern projector device based on vcsel

Abstract

The present application relates to the technical field of optical dot array projector, and especially relates to a regular dot array pattern projector device based on VCSEL, which receives configuration instructions through a parameter configuration module and outputs parameters such as lateral period, longitudinal period and offset; a light source generation module integrates a vertical cavity surface emitting laser chip, and generates laser beams with corresponding divergence angles according to arrangement parameters; an optical processing module includes a microlens array, a diffractive optical element or a mask element, the unit arrangement parameters of which are consistent with the configuration parameters, and the optical processing module performs beam splitting, diffraction or screening processing on the light beams; a distance control module calculates and maintains the working distance between the chip and the optical element based on the generalized Talbot principle; and a pattern generation module converts the processed light beams into regular dot array patterns and projects the regular dot array patterns to a target area. The present application does not need physical cutting and splicing of the microlens array, reduces the customization cost and detection complexity, improves the production yield and pattern accuracy, and is suitable for three-dimensional face recognition and industrial vision scenes.

Description

Technical Field

[0001] This invention relates to the field of optical dot matrix projector technology, and more particularly to a regular dot matrix pattern projector device based on VCSEL. Background Technology

[0002] A dot projector is a typical optical transmitter module in the field of 3D optical sensing applications. Common applications include 3D facial recognition functionality in smartphones and smart locks, and SLAM functionality in robotic vacuum cleaners and delivery robots. Its main function is to project a regularly or randomly arranged dot matrix for 3D modeling of the object or scene being measured. The number of projected dots varies depending on the required modeling precision of the application, ranging from dozens or hundreds to tens or even hundreds of thousands of dots.

[0003] Currently, the dot matrix projectors used in 3D optical sensing mainly consist of three parts: a laser source (such as EEL or VCSEL), a collimating lens (one or more lenses), and periodically arranged optical devices (DOE, MLA or Mask mentioned above). Among them, DOE is the most widely used optical device in mature mass-produced dot matrix projectors on the market.

[0004] The basic working principle of a dot matrix projector is as follows: the diverging light emitted by the laser source with a certain divergence angle is collimated into a parallel beam after passing through a collimating lens; the parallel beam is projected onto the DOE, and the diffraction function of the DOE splits the collimated beam into multiple collimated beams, thereby projecting a dot matrix pattern.

[0005] Existing dot projector technologies based on VCSELs and microlens arrays suffer from the following technical challenges: In 3D face recognition applications, generating high-precision regular dot patterns, such as rhombuses or hexagons, requires complex manufacturing processes. For example, physically cutting and splicing the microlens array to achieve half-cycle misalignment not only increases manufacturing steps and material waste but also introduces alignment errors and structural defects, leading to distortion or overlap of the dot pattern and affecting the accuracy and consistency of 3D facial modeling. Furthermore, the complex processes increase component customization costs and testing difficulty, reducing production yield and limiting the large-scale deployment of dot projectors in low-cost, high-reliability face recognition systems. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a regular dot matrix pattern projector device based on VCSEL. This invention solves the technical problems of high production costs and low yield caused by the complex process operations (such as MLA cutting and splicing) required to generate regular dot matrix patterns in existing dot matrix projector technologies.

[0007] To solve the above-mentioned technical problems, the specific contents of the present invention are as follows:

[0008] This invention provides a regular dot matrix pattern projector device based on VCSEL, comprising: The parameter configuration module receives the arrangement parameter configuration instruction of the regular dot matrix pattern and outputs the arrangement parameters, which include the horizontal period, the vertical period and the offset. The light source generation module includes a vertical cavity surface-emitting laser chip, which generates a laser beam with a corresponding divergence angle according to the arrangement parameters. An optical processing module includes optical elements, wherein the unit arrangement parameters of the optical elements are consistent with the arrangement parameters, receives the laser beam and performs optical processing, and outputs the processed beam; The distance control module calculates the working distance between the vertical cavity surface-emitting laser chip and the optical element based on the arrangement parameters, and maintains the working distance. The pattern generation module receives the processed light beam, generates a regular dot matrix pattern, and projects it onto the target area.

[0009] Furthermore, in the VCSEL-based regular dot matrix pattern projector device of the present invention, the optical processing module includes a microlens array, wherein the microlens units in the microlens array are periodically arranged according to the arrangement parameters. The microlens array receives the laser beam output by the light source generation module, and performs beam splitting on the laser beam through the microlens unit to output multiple sub-beams; The multiple sub-beams are collimated by the microlens unit and converted into a regularly distributed array of light spots; The pattern generation module receives the light spot array, projects the light spot array onto the target area, and generates the regular dot matrix pattern.

[0010] Furthermore, the optical processing module of the VCSEL-based regular dot matrix pattern projector device of the present invention includes a diffractive optical element, wherein the diffraction units of the diffractive optical element are periodically arranged according to the arrangement parameters. The diffractive optical element receives the laser beam output by the light source generation module, and modulates the wavefront of the laser beam through the etching structure on the surface of the diffractive unit to generate a phase-modulated beam. The phase-modulated beam undergoes diffraction, outputting multiple diffracted beams; The pattern generation module receives the multiple diffracted beams, integrates and processes them, and generates the regular dot matrix pattern in the target area.

[0011] Furthermore, the optical processing module of the VCSEL-based regular dot matrix pattern projector device of the present invention includes a mask element, wherein the light-transmitting holes of the mask element are periodically arranged according to the arrangement parameters. The mask element receives the laser beam output by the light source generation module, performs spatial filtering on the laser beam through the light-passing hole, and outputs the filtered beam. The pattern generation module receives the filtered light beam, converts the filtered light beam into a regularly distributed light spot pattern, and projects it onto the target area.

[0012] Furthermore, the light source generation module of the VCSEL-based regular dot matrix pattern projector device of the present invention includes a single-aperture vertical cavity surface-emitting laser chip; The single light-emitting aperture generates a single laser beam, which is then output to the optical processing module. The optical processing module receives the single laser beam, performs optical processing on the single laser beam, and outputs the processed beam. The pattern generation module receives the processed light beam, converts the processed light beam into a complete regular dot matrix pattern, and projects it onto the target area.

[0013] Furthermore, the light source generation module of the VCSEL-based regular dot matrix pattern projector device of the present invention includes a multi-aperture array vertical cavity surface-emitting laser chip, wherein the arrangement period of the multi-aperture array matches the unit arrangement period of the optical element. Each light-emitting aperture in the multi-light-emitting aperture array independently generates a laser beam, and all the laser beams are simultaneously output to the optical processing module. The optical processing module receives all the laser beams, processes the laser beams in parallel, and outputs the processed beams. The processed light beam forms a light spot distribution in the target area, and the light spots in the light spot distribution overlap each other. The pattern generation module receives the light spot distribution, optimizes the light spot distribution, and generates an optimized regular dot matrix pattern.

[0014] Furthermore, the multi-emitting aperture array of the VCSEL-based regular dot matrix pattern projector device of the present invention is arranged in a square or hexagonal pattern. When the multi-emitting aperture array is arranged in a square, the emitting apertures are distributed at equal intervals in both the horizontal and vertical directions; When the multi-emitting aperture array is arranged in a hexagonal pattern, the emitting apertures are arranged in a hexagonal grid. The pattern generation module adjusts the projection parameters according to the arrangement of the multi-emitting aperture array. After the projection parameters are adjusted, the pattern generation module generates a regular dot matrix pattern with the corresponding arrangement.

[0015] Furthermore, the distance control module of the VCSEL-based regular dot matrix pattern projector device of the present invention includes a distance detection unit and a distance adjustment unit; The distance detection unit monitors the actual distance between the vertical cavity surface-emitting laser chip and the optical element in real time and outputs the distance monitoring result. The distance adjustment unit receives the distance monitoring result and corrects the actual distance based on the distance monitoring result to keep the actual distance within a preset range; When the actual distance remains within a preset range, the pattern generation module begins to receive the light beam output by the optical processing module and generates the regular dot matrix pattern.

[0016] Furthermore, the regular dot matrix pattern of the VCSEL-based regular dot matrix pattern projector device of the present invention includes a rhombic arrangement or a hexagonal arrangement; For a regular rhombus arrangement, the cell offset of the optical processing module is set to a half-period value; For the hexagonal arrangement, the units of the optical processing module are arranged according to a hexagonal grid; The optical processing module processes the laser beam according to the set unit parameters and outputs beams arranged accordingly. The pattern generation module receives the correspondingly arranged light beams and generates a regular dot matrix pattern with a rhombus or hexagonal arrangement.

[0017] Furthermore, the VCSEL-based regular dot matrix pattern projector device of the present invention also includes a quality monitoring module; The quality monitoring module acquires pattern images of the target area in real time and analyzes the pattern images to obtain pattern quality parameters. When the pattern quality parameters do not meet the preset standards, the quality monitoring module sends a distance adjustment signal to the distance control module; The distance control module receives the distance adjustment signal and adjusts the distance between the vertical cavity surface-emitting laser chip and the optical element according to the distance adjustment signal. After the distance is adjusted, the pattern generation module receives the light beam output by the optical processing module again and regenerates the regular dot matrix pattern. The quality monitoring module continues to monitor the pattern quality parameters until the pattern quality parameters meet the preset standards.

[0018] Beneficial effects of this invention; This invention directly receives and outputs the arrangement parameters of a regular dot matrix pattern through a parameter configuration module, including the horizontal period, vertical period, and offset. This ensures that the arrangement parameters of the optical element units in the optical processing module are consistent with the desired pattern, avoiding the complex process of physical cutting and splicing of microlens arrays in existing technologies. This simplifies manufacturing steps, reduces material waste, and eliminates alignment errors. The light source generation module adjusts the divergence angle of the vertical cavity surface-emitting laser chip according to the arrangement parameters, outputting a matching laser beam. Combined with the working distance calculated and maintained by the distance control module based on the generalized Talbot principle, this ensures efficient beam splitting or diffraction in the optical processing module, generating a high-precision regular dot matrix pattern. This modular design reduces component customization costs and testing difficulty, improves production yield, and enhances the adaptability and reliability of the device in dynamic environments by acquiring pattern images in real time and providing feedback adjustments. This promotes the large-scale deployment of dot matrix projectors in scenarios such as 3D face recognition. Attached Figure Description

[0019] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on the drawings without creative effort.

[0020] Figure 1 The structure of the diffractive optical element (DOE) of the present invention includes a real image of the step morphology of a periodic unit (left part) and a schematic diagram of the DOE formed by multiple periodic units arranged periodically (right part).

[0021] Figure 2 The layout of the microlens array (MLA) of the present invention shows that the microlens units are arranged periodically.

[0022] Figure 3 The structure of the mask of the present invention includes a periodic arrangement of light-transmitting holes (white parts) and opaque parts (black parts).

[0023] Figure 4 The present invention includes a regular dot matrix pattern (left part, with periodic arrangement) and a random dot matrix pattern (right part, with disordered arrangement).

[0024] Figure 5 This is a schematic diagram illustrating the definition of offset (ds) in the dot matrix pattern of the present invention.

[0025] Figure 6 Examples of various typical regular dot matrix patterns and their parameters are provided for this invention. Detailed Implementation

[0026] To make the technical solution of the present invention clearer, the present invention will be clearly and completely described below with reference to specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The present invention provided by various embodiments will be described in detail below with reference to the accompanying drawings. To better understand the purpose of the present invention, the present invention will be described in further detail below.

[0027] One major drawback of existing products in this field is their complex manufacturing process. To achieve a rhomboid dot matrix pattern, multiple steps are required, including cutting (cutting off half a cycle), splicing, translating (translating another half cycle), and rotating the MLA. This complexity naturally introduces errors, leading to increased costs and reduced yield. For this projector product, AMS has a complex QC inspection process just for detecting the cutting, bonding, and rotation of the MLA. In contrast, this invention eliminates the need for any cutting of the MLA; standard MLA can be used directly to achieve dot matrix patterns other than square arrangements.

[0028] Another drawback of the AMS technology approach is the limitation of its dot matrix patterns. Square dot matrices are the most basic type, easily achieved using square-arranged point light sources and MLA (Multi-Layer Atmosphere). For rhomboid dot matrices, AMS can also achieve this using a complex "semi-periodic misalignment" method, building upon square-arranged point light sources and MLA. However, this technology approach is incapable of handling other dot matrix patterns, especially the hexagonal dot matrix patterns that are extremely common in optical sensing.

[0029] This invention provides a regular dot matrix pattern projector device based on VCSEL, comprising: The parameter configuration module receives the arrangement parameter configuration instruction of the regular dot matrix pattern and outputs the arrangement parameters, which include the horizontal period, the vertical period and the offset. The light source generation module includes a vertical cavity surface-emitting laser chip, which generates a laser beam with a corresponding divergence angle according to the arrangement parameters. An optical processing module includes optical elements, wherein the unit arrangement parameters of the optical elements are consistent with the arrangement parameters, receives the laser beam and performs optical processing, and outputs the processed beam; The distance control module calculates the working distance between the vertical cavity surface-emitting laser chip and the optical element based on the arrangement parameters, and maintains the working distance. The pattern generation module receives the processed light beam, generates a regular dot matrix pattern, and projects it onto the target area.

[0030] The VCSEL-based regular dot matrix pattern projector device achieves efficient dot matrix generation through modular design, making it suitable for scenarios such as 3D face recognition and industrial vision. The parameter configuration module receives regular dot matrix pattern arrangement parameter configuration instructions from external systems or users, including key parameters such as horizontal period, vertical period, and offset. After parsing the instructions, the module outputs the arrangement parameters, which directly determine the geometric layout of the dot matrix pattern, such as a rhombus or hexagonal arrangement. These arrangement parameters are passed to subsequent modules, providing a unified configuration basis for this invention.

[0031] The light source generation module integrates a vertical-cavity surface-emitting laser (VCSEL) chip. This chip adjusts the divergence angle of the laser beam based on its arrangement parameters. The VCSEL chip can employ a single-aperture or multi-aperture array structure. The arrangement period of the multi-aperture array matches the unit arrangement period of the optical elements to ensure consistent beam output. The laser beam generation process is based on semiconductor excitation principles, and the beam divergence angle is dynamically adjusted via the chip's driving circuitry to adapt to different pattern requirements. The control of the divergence angle directly affects the beam propagation efficiency within the optical processing module.

[0032] The optical processing module includes optical components such as microlens arrays, diffractive optical elements, and mask elements. The unit arrangement parameters of these optical components are consistent with the arrangement parameters output by the parameter configuration module. The microlens array splits and collimates the incident laser beam through microlens units, outputting multiple sub-beams to form a spot array. The diffractive optical elements modulate the wavefront phase of the laser beam using surface etching structures, generating a diffraction effect to output multiple diffracted beams. The mask elements filter the beam through the spatial filtering effect of their apertures, preserving regularly distributed optical signals. The output beam of the optical processing module carries the original information of the spot pattern, laying the foundation for pattern generation.

[0033] First, based on the arrangement of the dot matrix pattern to be projected, the arrangement parameters of the micro-units on the optical element are determined by combining the generalized Talbot principle formula, specifically the horizontal period dx, the vertical period dy, and the displacement ds.

[0034] The optical structure of individual micro-units on an optical element is designed based on the overall field-of-view of the dot matrix pattern. For MLA, this is determined by the lens surface shape of the microlens unit; for DOE, it is determined by the micro / nano etching structure of the DOE micro-units; and for masks, it is determined by the shape of the openings on the mask.

[0035] The VCSEL chip is designed based on the overall brightness or optical power requirements of the dot matrix pattern. If the VCSEL is a single-aperture chip, placing it at a Talbot distance z0 from the optical element is sufficient to project a dot matrix pattern, without needing to consider horizontal (x-direction) or vertical (y-direction) alignment. However, if the VCSEL chip is a combination of multiple single-aperture chips or a multi-aperture array chip, then the spacing between the apertures must be an integer multiple of the horizontal and vertical periods of the optical element's micro-units, respectively; otherwise, a clear dot matrix pattern cannot be projected.

[0036] The distance control module calculates the working distance between the vertical-cavity surface-emitting laser (VCSEL) chip and optical components based on the arrangement parameters. The calculation follows the generalized Talbot principle model, avoiding the simplification of using a collimating lens. The module integrates a distance detection unit and a distance adjustment unit. The distance detection unit monitors the actual distance in real time and outputs the monitoring results, while the distance adjustment unit drives the mechanical structure to fine-tune the relative positions of the chip and components based on the monitoring results. Maintaining the working distance is achieved through a closed-loop feedback mechanism, such as triggering distance correction when pattern quality fluctuates, ensuring the stability of the dot matrix projection.

[0037] The pattern generation module receives the processed light beam from the optical processing module, converts the beam into a regular dot matrix pattern, and projects it onto the target area. The module generates the pattern using an optical projection lens or free-space propagation, resulting in a high-contrast distribution of light spots on the target surface. The pattern generation process considers the beam superposition effect; for multi-aperture array light sources, the light spot distribution is optimized to eliminate overlap or distortion. The generated dot matrix pattern can be used in a 3D modeling system, where depth data is extracted by analyzing pattern distortion.

[0038] The device also integrates a quality monitoring module, which acquires pattern images of the target area in real time and analyzes pattern quality parameters such as dot matrix uniformity or alignment. When the quality parameters deviate from the preset standard, the quality monitoring module sends a distance adjustment signal to the distance control module, triggering a recalibration of the working distance. After calibration, the pattern generation module reprojects the dot matrix pattern, iteratively optimizing until the quality parameters meet the standard. This design improves the device's adaptability in dynamic environments and reduces the need for manual intervention. The quality monitoring module acquires pattern images of the target area through a CMOS sensor and analyzes quality parameters such as dot matrix uniformity or alignment. When the parameters deviate from the preset standard, the quality monitoring module sends a distance adjustment signal to the distance control module, triggering a recalibration of the working distance. After calibration, the pattern generation module reprojects the dot matrix pattern, iteratively optimizing until the quality parameters meet the standard.

[0039] This invention achieves flexible generation of regular dot matrix patterns through modular collaborative operation, with data flow and physical connections between modules optimized synchronously based on arrangement parameters. In practical applications, such as facial recognition in smart door locks, the device dynamically configures parameters according to recognition distance and accuracy requirements. The light source generation module outputs a low-divergence-angle beam, the optical processing module uses a microlens array for beam splitting, and the distance control module maintains a short working distance to achieve high-density dot matrix projection. This modular approach reduces customization costs and promotes the large-scale deployment of dot matrix projectors in low-cost, high-reliability systems.

[0040] In the VCSEL-based regular dot matrix pattern projector device, the optical processing module includes a microlens array. The microlens units are arranged periodically according to parameters, with the lateral period, longitudinal period, and offset directly determining the spatial distribution of the microlenses. The microlens array receives the laser beam output from the light source generation module. Each microlens unit corresponds to a beam splitting point, dividing the incident beam into multiple sub-beams through refraction. These sub-beams are collimated by the microlens units, and the lens surface is optimized to reduce the divergence angle, resulting in a highly parallel light dot array. The pattern generation module receives the light dot array and uses an optical projection lens to image it onto the target area, forming a regular dot matrix pattern. The unit arrangement of the microlens array is consistent with the output of the parameter configuration module, avoiding manual cutting or splicing and reducing process complexity.

[0041] The optical processing module may also include diffractive optical elements. The diffractive units are arranged periodically according to arrangement parameters, and the etching structure on the unit surface is designed based on the wavefront phase modulation principle. After receiving a laser beam, the diffractive optical elements introduce a phase delay through etching steps, causing diffraction and outputting multiple diffracted beams. The diffraction angle is determined by both the unit period and the wavelength. The pattern generation module focuses and integrates these multiple diffracted beams to generate a high-contrast dot pattern in the target area. The use of diffractive optical elements expands the flexibility of the dot pattern, making it suitable for non-square arrangements such as hexagons.

[0042] As another implementation method for optical processing modules, mask elements have apertures arranged periodically according to a set of parameters, and the shape of the apertures is customized through photolithography. After receiving a laser beam, the mask element blocks part of the beam and retains a regularly distributed light signal through the spatial filtering effect of the apertures. The pattern generation module converts the filtered beam into a dot pattern and projects it onto the target area. Mask elements are low-cost and suitable for large-scale deployment, and the aperture arrangement parameters directly match the dot pattern requirements.

[0043] The light source generation module can employ a single-aperture vertical-cavity surface-emitting laser (VCSEL) chip. The single aperture generates a single laser beam, and the beam divergence angle is dynamically adjusted via a driving circuit. The optical processing module receives the single laser beam and uses the beam-splitting or diffraction capabilities of periodic optical elements to expand the single beam into a complete dot matrix pattern. The pattern generation module directly processes the split beam, eliminating the need for multi-source alignment and simplifying the device structure. The single-aperture solution is suitable for low-power applications, such as portable facial recognition devices.

[0044] In a multi-aperture array vertical-cavity surface-emitting laser (VCSEL) chip, the arrangement period of the apertures matches the unit arrangement period of the optical elements, and each aperture emits a laser beam independently. The optical processing module processes multiple incident beams in parallel, and the output beams form a spot distribution in the target area; superposition effects may occur between these spots. The pattern generation module optimizes the spot distribution using algorithms, eliminating overlap or distortion to generate a uniform and regular dot matrix pattern. The multi-aperture array improves pattern brightness, making it suitable for industrial vision scenarios with high ambient light interference.

[0045] The multi-aperture array can be arranged in a square or hexagonal pattern. In a square arrangement, the apertures are evenly spaced in both the horizontal and vertical directions; in a hexagonal arrangement, they are arranged in a hexagonal grid. The pattern generation module adjusts projection parameters, such as projection angle or focal length, based on the aperture arrangement to ensure the output pattern matches the arrangement parameters. Square arrangements are easier to align, while hexagonal arrangements offer higher dot density, making them suitable for detailed 3D modeling.

[0046] The distance control module includes a distance detection unit and a distance adjustment unit. The distance detection unit monitors the actual distance between the VCSEL chip and the optical element in real time using a laser rangefinder or optical encoder. After receiving the monitoring results, the distance adjustment unit drives a piezoelectric ceramic or stepper motor to fine-tune the relative position, keeping the actual distance within a preset range. The pattern generation module starts working after the distance stabilizes, avoiding dot matrix blurring caused by distance fluctuations. The closed-loop feedback mechanism of the distance control module improves the reliability of the device in dynamic environments.

[0047] Regular dot matrix patterns include rhombic or hexagonal arrangements. Rhombic arrangements are achieved by setting the cell offset of the optical processing module to a half-period value, while hexagonal arrangements require the cells to be arranged in a hexagonal grid. The optical processing module modulates the wavefront distribution of the laser beam according to the cell parameters, and the output beam carries specific arrangement information. The pattern generation module projects the beam onto the target area, and the geometric properties of the dot matrix pattern directly support three-dimensional depth calculations, such as facial feature extraction.

[0048] The device can also integrate a quality monitoring module. This module acquires pattern images of the target area using CMOS or CCD sensors, and image processing algorithms analyze quality parameters such as dot matrix uniformity and alignment. When these parameters deviate from preset standards, the quality monitoring module sends an adjustment signal to the distance control module, triggering distance recalibration. The pattern generation module then reprojects the dot matrix pattern, iteratively optimizing until the quality parameters meet the standards. The application of the quality monitoring module reduces manual intervention and is suitable for long-term industrial automation systems.

[0049] In 3D face recognition and industrial vision scenarios, the VCSEL-based regular dot matrix pattern projector simplifies the dot matrix pattern generation process through modular design. The parameter configuration module receives configuration instructions from external systems or users, including arrangement parameters such as horizontal period, vertical period, and offset. After parsing, the module outputs these parameters to define the geometric layout of the dot matrix pattern. For example, in smart door lock applications, users can set the parameters for a rhombus arrangement via an interface, with both the horizontal and vertical periods at 50 micrometers and the offset set to half a period value. The parameter configuration module then passes these parameters to subsequent modules, providing a unified configuration for this invention.

[0050] The light source generation module integrates a vertical-cavity surface-emitting laser (VCSEL) chip, which adjusts the divergence angle of the laser beam according to the arrangement parameters. The VCSEL chip can employ a single-aperture structure, generating a single laser beam. The beam divergence angle is dynamically adjusted by the driving circuit to adapt to different pattern requirements. In a multi-aperture array configuration, the aperture arrangement period matches the unit arrangement period of the optical elements. Each aperture emits a laser beam independently, and all beams are synchronously output to the optical processing module. The multi-aperture array can be arranged in a square or hexagonal pattern. In a square arrangement, the apertures are evenly spaced in both the horizontal and vertical directions; in a hexagonal arrangement, they are arranged in a hexagonal grid to increase pattern density.

[0051] The optical processing module includes a microlens array, diffractive optical elements, or a mask element. The unit arrangement parameters of the optical elements are consistent with the arrangement parameters output by the parameter configuration module. The microlens units in the microlens array are arranged periodically according to the arrangement parameters. After receiving a laser beam, the beam is split into multiple sub-beams by the beam-splitting effect of the microlens units. These sub-beams are then collimated to form a regularly distributed array of light spots. The diffractive optical elements modulate the wavefront phase of the laser beam using surface etching structures, generating a diffraction effect and outputting multiple diffracted beams. The diffraction angle is determined by the unit period and wavelength. The mask element filters the beam through the spatial filtering effect of its aperture, retaining only the regularly distributed optical signals. The output beam of the optical processing module carries dot pattern information, directly supporting pattern generation.

[0052] The distance control module calculates the working distance between the vertical-cavity surface-emitting laser (VCSEL) chip and optical components based on the arrangement parameters. This distance calculation follows the generalized Talbot principle model, avoiding the use of existing collimating lenses. The module integrates a distance detection unit and a distance adjustment unit. The distance detection unit monitors the actual distance in real time using a laser rangefinder and outputs the monitoring results. Upon receiving the monitoring results, the distance adjustment unit drives a piezoelectric ceramic actuator to fine-tune the relative position of the chip and components, keeping the actual distance within a preset range. The pattern generation module begins operation after the distance stabilizes to prevent dot matrix blurring.

[0053] The pattern generation module receives the light beam output from the optical processing module, converts the beam into a regular dot matrix pattern, and projects it onto the target area. The module images the light through an optical projection lens, creating a high-contrast distribution of light spots on the target surface. For multi-aperture array light sources, the pattern generation module optimizes the light spot distribution using algorithms to eliminate superposition or distortion, generating a uniform pattern. In a 3D face recognition scenario, the dot matrix pattern is projected onto the face surface, and after the reflected pattern is captured by the camera, the system analyzes the distortion to extract depth data.

[0054] The device also integrates a quality monitoring module, which acquires pattern images of the target area using a CMOS sensor. Image processing algorithms analyze quality parameters such as pattern uniformity and alignment. When these parameters deviate from preset standards, the quality monitoring module sends a distance adjustment signal to the distance control module, triggering a recalibration of the working distance. The pattern generation module then reprojects the dot matrix pattern, iteratively optimizing until the quality parameters meet the standards. This closed-loop control mechanism is suitable for long-term industrial automation systems, such as the SLAM function of a sweeping robot, where the device dynamically adjusts parameters to cope with environmental changes.

[0055] This invention achieves flexible generation of dot matrix patterns through modular collaboration, with data flow between modules optimized synchronously based on arrangement parameters. In practical applications, such as in UAV navigation scenarios, the device configures parameters according to flight altitude and accuracy requirements. The light source generation module outputs a low-divergence-angle beam, the optical processing module uses a microlens array for beam splitting, and the distance control module maintains a short working distance to achieve high-density dot matrix projection. This design avoids the cutting and splicing processes of microlens arrays, reduces component customization costs and testing difficulties, and promotes the large-scale deployment of dot matrix projectors in low-cost systems.

[0056] This invention directly receives the configuration instructions for the arrangement parameters of a regular dot matrix pattern through a parameter configuration module and outputs key parameters such as the horizontal period, vertical period, and offset. This ensures that the arrangement parameters of the optical element units in the optical processing module are completely consistent with the geometric layout of the desired pattern. In a 3D face recognition door lock system, when the user sets the parameters for a rhombus dot matrix pattern, the parameter configuration module outputs parameters such as a horizontal period of 50 micrometers, a vertical period of 50 micrometers, and an offset of 25 micrometers. The microlens array of the optical processing module directly uses commercially available standard products, and the microlens units are automatically aligned according to the arrangement parameters, eliminating the need for physical cutting and splicing of the microlens array.

[0057] The light source generation module integrates a vertical-cavity surface-emitting laser (VCSEL) chip, which dynamically adjusts the divergence angle of the laser beam based on its arrangement parameters. The optical processing module includes a microlens array, diffractive optical elements, or mask elements, with the unit arrangement parameters and configuration parameters of these optical elements synchronized. The microlens array splits and collimates the incident laser beam through its microlens units. The diffractive optical elements modulate the beam wavefront phase using surface etching structures, and the mask elements achieve spatial filtering through light-passing apertures. This design allows for the direct configuration of square or hexagonal dot patterns through parameter settings, avoiding the complex cutting, misalignment, and splicing operations required in existing processes.

[0058] The distance control module calculates the working distance between the vertical-cavity surface-emitting laser chip and optical components based on the generalized Talbot principle, and maintains the optimal working distance through a distance detection unit and a distance adjustment unit. In practical applications of smart locks, when ambient temperature fluctuations cause distance deviations, the quality monitoring module acquires real-time images of the target area pattern, analyzes quality parameters such as dot matrix uniformity, and automatically triggers a distance recalibration mechanism. The pattern generation module reprojects the dot matrix pattern, iteratively optimizing until the quality meets the standards. This closed-loop control mechanism significantly reduces process complexity, allowing the use of standard components instead of custom parts, and greatly reducing material waste and alignment errors.

[0059] This invention simplifies the complex processes required by existing dot matrix projectors to a parameter configuration operation through modular collaborative work. In industrial parts sorting scenarios, the device can generate a hexagonal high-density dot matrix by adjusting the arrangement parameters, without requiring structural modifications to the optical components. This design significantly reduces production costs and inspection difficulty, improves production yield, and promotes the large-scale application of dot matrix projectors in low-cost, high-reliability systems.

[0060] The specific process by which the distance control module calculates the working distance is as follows. The generalized Talbot relationship is expressed by the following formula: ; in: This indicates the working distance between the vertical-cavity surface-emitting laser chip and the optical components. Indicates the horizontal period; Indicates the longitudinal period; Indicates the offset; Indicates the wavelength of the incident laser; , , Indicates an integer parameter.

[0061] When calculating the working distance, the parameter configuration module first receives the configuration instructions for the arrangement parameters of the regular dot matrix pattern and outputs the lateral period, longitudinal period, and offset. The light source generation module determines the laser wavelength based on the characteristics of the vertical-cavity surface-emitting laser chip, such as 850 nm or 940 nm. The integer parameters L, M, and N are selected according to design requirements, such as through simulation or experimental optimization, to ensure that the working distance is feasible within the actual device size range. Typical values ​​can be set to L=1, M=1, N=0, or adjusted according to the arrangement of the dot matrix pattern. During calculation, the lateral period, longitudinal period, offset, wavelength, and integer parameters are substituted into the formula to obtain the working distance value. The distance control module monitors the actual distance in real time through the distance detection unit and compares it with the calculated value. The distance adjustment unit drives the mechanical structure to make fine adjustments to maintain a stable working distance. This calculation path ensures the generation accuracy of the regular dot matrix pattern and avoids alignment errors in existing processes.

[0062] In practical implementation, for example, when the regular dot matrix pattern is arranged in a regular rhombus, the offset is set to half a period value, with the horizontal and vertical periods being equal. The microlens unit arrangement parameters of the optical processing module are consistent with the arrangement parameters, eliminating the need for physical cutting. When calculating the working distance, if the horizontal period is 50 micrometers, the vertical period is 50 micrometers, the offset is 25 micrometers, the wavelength is 940 nanometers, and the integer parameters L=1, M=1, N=1, then the calculated working distance is approximately 2.13 millimeters. The distance control module maintains this distance, and the pattern generation module projects a high-density dot matrix pattern. The quality monitoring module acquires pattern images in real time; if environmental changes cause distance offset, it triggers recalculation and adjustment to ensure dot matrix uniformity.

[0063] Embodiment 1 of the present invention; In the 3D face recognition door lock system, the parameter configuration module receives user-defined rhomboid dot matrix pattern parameters, with a horizontal period of 50 micrometers, a vertical period of 50 micrometers, and an offset set to a half-period value of 25 micrometers. The light source generation module uses a multi-aperture vertical-cavity surface-emitting laser chip, with the apertures arranged in a square and their period matching the microlens unit. The microlens array in the optical processing module directly uses commercially available standard products, and the microlens units are automatically aligned according to the arrangement parameters issued by the parameter configuration module, without the need for physical cutting. The laser beam is split by the microlens to form a sub-beam array. The distance control module calculates and maintains a working distance of 2 millimeters between the chip and the optical elements based on the generalized Talbot principle. The pattern generation module projects the light dot array onto the face surface, achieving a dot density of 400 dots per square millimeter with an edge distortion rate of less than 5%. The quality monitoring module uses a CMOS sensor to detect the dot matrix alignment in real time. When ambient temperature fluctuations cause a distance offset of 0.1 millimeters, the distance adjustment unit is automatically triggered for calibration to keep the dot matrix pattern stable.

[0064] Embodiment 2 of the present invention; For industrial parts sorting scenarios, the device needs to generate a high-density hexagonal dot matrix. The parameter configuration module sets the horizontal period to 40 micrometers and the vertical period to 40 micrometers, with the units arranged in a hexagonal grid. The light source generation module uses a single-aperture vertical-cavity surface-emitting laser chip, with the divergence angle adjusted to 15 degrees to adapt to close-range projection. The optical processing module uses diffractive optical elements, and its etching step depth is optimized to 155 nanometers according to the wavelength, keeping the diffraction spot size within 10 micrometers. The distance control module fine-tunes the distance to 1.5 millimeters using a piezoelectric ceramic actuator, achieving an accuracy of 0.01 millimeters. The pattern generation module forms a hexagonal dot matrix on the surface of the parts, with a dot matrix overlap rate of less than 3%, enabling sub-millimeter-level depth measurement in conjunction with a vision system. Under strong ambient light interference, the quality monitoring module detects pattern degradation through a contrast algorithm and dynamically adjusts the laser power to 120% of the initial value to ensure the usability of the dot matrix.

[0065] Explanation of technical terms in this invention: VCSEL (Vertical Cavity Surface Emitting Laser) is a type of semiconductor laser. LD (Laser Diode) is a general term for semiconductor lasers. An edge-emitting laser (EEL) is a typical laser diode. DOE (Diffractive Optical Element) is a two-dimensional diffraction grating formed by etching micro- and nano-scale stepped patterns onto the surface of silicon or other transparent materials. Figure 1The diagram shows the actual step shape of a single periodic cell on a DOE device (left) and a schematic diagram of a DOE formed by multiple periodic cells arranged periodically (right).

[0066] MLA (Micro Lens Array) is similar to DOE, except that each periodic unit is no longer a micro- or nano-sized etching step, but a micron-scale microlens, such as... Figure 2 exhibit.

[0067] A mask is essentially a miniature film on which patterns are drawn or etched. For example... Figure 3 The mask shown has black areas that are opaque and white areas that are transparent.

[0068] Optical elements with periodic unit arrangement: The DOE, MLA and Mask examples shown above are all composed of periodically arranged units, and are called periodically arranged optical elements.

[0069] A dot projector is a device that can project a dot pattern. Its core components are a combination of one of the lasers and one of the optical elements mentioned above. The laser illuminates the optical element to project the dot pattern.

[0070] Regular dot matrix patterns: As the name suggests, regular dot matrix patterns are patterns where the dots appear to be arranged in a regular, periodic pattern (e.g., ...). Figure 4 (Left image), rather than a messy, randomly arranged dot matrix (such as...) Figure 4 (Right image).

[0071] In most optical sensing applications, typical regular dot matrix patterns can be determined by three parameters: horizontal period (dx), vertical period (dy), and offset or slip (ds). dx and dy are relatively easy to understand. The offset ds refers to the amount by which a row of dots is displaced from its alignment position relative to its adjacent row. (See [link to relevant documentation]). Figure 5 .

[0072] Based on this definition, we can examine, for example... Figure 6 The typical regular dot matrix pattern and its corresponding parameters.

Claims

1. A regular dot matrix pattern projector device based on VCSEL, characterized in that, include: The parameter configuration module receives the arrangement parameter configuration instruction of the regular dot matrix pattern and outputs the arrangement parameters, which include the horizontal period, the vertical period and the offset. The light source generation module includes a vertical cavity surface-emitting laser chip, which generates a laser beam with a corresponding divergence angle according to the arrangement parameters. An optical processing module includes optical elements, wherein the unit arrangement parameters of the optical elements are consistent with the arrangement parameters, receives the laser beam and performs optical processing, and outputs the processed beam; The distance control module calculates the working distance between the vertical cavity surface-emitting laser chip and the optical element based on the arrangement parameters, and maintains the working distance. The pattern generation module receives the processed light beam, generates a regular dot matrix pattern, and projects it onto the target area.

2. The VCSEL-based regular dot matrix pattern projector device according to claim 1, characterized in that, The optical processing module includes a microlens array, wherein the microlens units in the microlens array are periodically arranged according to the arrangement parameters. The microlens array receives the laser beam output by the light source generation module, and performs beam splitting on the laser beam through the microlens unit to output multiple sub-beams; The multiple sub-beams are collimated by the microlens unit and converted into a regularly distributed array of light spots; The pattern generation module receives the light spot array, projects the light spot array onto the target area, and generates the regular dot matrix pattern.

3. The VCSEL-based regular dot matrix pattern projector device according to claim 2, characterized in that, The optical processing module includes a diffractive optical element, wherein the diffraction units of the diffractive optical element are periodically arranged according to the arrangement parameters. The diffractive optical element receives the laser beam output by the light source generation module, and modulates the wavefront of the laser beam through the etching structure on the surface of the diffractive unit to generate a phase-modulated beam. The phase-modulated beam undergoes diffraction, outputting multiple diffracted beams; The pattern generation module receives the multiple diffracted beams, integrates and processes them, and generates the regular dot matrix pattern in the target area.

4. The VCSEL-based regular dot matrix pattern projector device according to claim 3, characterized in that, The optical processing module includes a mask element, wherein the light-transmitting holes of the mask element are periodically arranged according to the arrangement parameters; The mask element receives the laser beam output by the light source generation module, performs spatial filtering on the laser beam through the light-passing hole, and outputs the filtered beam. The pattern generation module receives the filtered light beam, converts the filtered light beam into a regularly distributed light spot pattern, and projects it onto the target area.

5. The VCSEL-based regular dot matrix pattern projector device according to claim 4, characterized in that, The light source generation module includes a single-aperture vertical cavity surface-emitting laser chip. The single light-emitting aperture generates a single laser beam, which is then output to the optical processing module. The optical processing module receives the single laser beam, performs optical processing on the single laser beam, and outputs the processed beam. The pattern generation module receives the processed light beam, converts the processed light beam into a complete regular dot matrix pattern, and projects it onto the target area.

6. The VCSEL-based regular dot matrix pattern projector device according to claim 5, characterized in that, The light source generation module includes a multi-aperture array vertical cavity surface-emitting laser chip, wherein the arrangement period of the multi-aperture array matches the unit arrangement period of the optical element. Each light-emitting aperture in the multi-light-emitting aperture array independently generates a laser beam, and all the laser beams are simultaneously output to the optical processing module. The optical processing module receives all the laser beams, processes the laser beams in parallel, and outputs the processed beams. The processed light beam forms a light spot distribution in the target area, and the light spots in the light spot distribution overlap each other. The pattern generation module receives the light spot distribution, optimizes the light spot distribution, and generates an optimized regular dot matrix pattern.

7. The VCSEL-based regular dot matrix pattern projector device according to claim 6, characterized in that, The multi-emitting aperture array is arranged in a square or hexagonal pattern; When the multi-emitting aperture array is arranged in a square, the emitting apertures are distributed at equal intervals in both the horizontal and vertical directions; When the multi-emitting aperture array is arranged in a hexagonal pattern, the emitting apertures are arranged in a hexagonal grid. The pattern generation module adjusts the projection parameters according to the arrangement of the multi-emitting aperture array. After the projection parameters are adjusted, the pattern generation module generates a regular dot matrix pattern with the corresponding arrangement.

8. The VCSEL-based regular dot matrix pattern projector device according to claim 7, characterized in that, The distance control module includes a distance detection unit and a distance adjustment unit; The distance detection unit monitors the actual distance between the vertical cavity surface-emitting laser chip and the optical element in real time and outputs the distance monitoring result. The distance adjustment unit receives the distance monitoring result and corrects the actual distance based on the distance monitoring result to keep the actual distance within a preset range; When the actual distance remains within a preset range, the pattern generation module begins to receive the light beam output by the optical processing module and generates the regular dot matrix pattern.

9. The VCSEL-based regular dot matrix pattern projector device according to claim 8, characterized in that, The regular dot matrix pattern includes a rhombus arrangement or a hexagonal arrangement; For a regular rhombus arrangement, the cell offset of the optical processing module is set to a half-period value; For the hexagonal arrangement, the units of the optical processing module are arranged according to a hexagonal grid; The optical processing module processes the laser beam according to the set unit parameters and outputs beams arranged accordingly. The pattern generation module receives the correspondingly arranged light beams and generates a regular dot matrix pattern with a rhombus or hexagonal arrangement.

10. The VCSEL-based regular dot matrix pattern projector device according to claim 9, characterized in that, It also includes a quality monitoring module; The quality monitoring module acquires pattern images of the target area in real time and analyzes the pattern images to obtain pattern quality parameters. When the pattern quality parameters do not meet the preset standards, the quality monitoring module sends a distance adjustment signal to the distance control module; The distance control module receives the distance adjustment signal and adjusts the distance between the vertical cavity surface-emitting laser chip and the optical element according to the distance adjustment signal. After the distance is adjusted, the pattern generation module receives the light beam output by the optical processing module again and regenerates the regular dot matrix pattern. The quality monitoring module continues to monitor the pattern quality parameters until the pattern quality parameters meet the preset standards.

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